Stoker pusher bar



Dec. 30, 1947. J. s. sKELLY STOKER PU`SHERvBAR Filed March 12, 1945 INVENTOR.

Patented Dec. 30, 1947 STOKER.y PUSHER BAR John S. Skelly, Monongahela, Pa., assgnor to Combustion Engineering Company, Inc.,' New York, N. Y.

Application March 12, 19475, Serial No. 582,311

This invention relates to stokers for fuels and particularly to improvements in the retort type of Stoker. i

In one formof retort Stoker, the fuel is advanced through the retort by pushers comprisingwedge-shaped blocks having a steep inclined face extending upwardly inthe retort on the side of the blocksfacing the direction of the fuel movement and a fiat inclined face sloping upwardly toward the steep face on the side of the blocks facing in the opposite direction. These blocks are usually mounted on a bar which slides on the bottom of the retort and is moved back and forth by driving means, thereby reciprocating the pushers and causing the fuel to be advanced through the retort. It has been found that during operation, the fuel works into the space between the bar and the bottom of the retort, packs there and exertsy an upward pressure on the bar tending to lift it. This pressure is resisted by the bearings for the bar at the ends of the retort thereby increasing the pressure thereon and tends to bend the bar upwardly. This results in an increase in bar friction and bearing wear and consequently of the power to drive the stoker.

It is an object of this invention to provide an improved pusher bar which will overcome the above objections.

Figure 1 is a longitudinal sectional View through a retort of a stoker embodying the improved bar.

Figure 2 is a transverse section through the retort and improved bar taken on line 2--2 in Figure 1;

Figure 3 is a top plan View of the improved bar; and

Figure 4 is a bottom view of the improved bar.

The stoker illustrated comprises a retort I to which coal is fed from a hopper II by means of a screw I2, and containing a movable pusher bar I3 having auxiliary distributors, agitators or pushers I4` thereon arranged to advance and distribute the coal uniformly over the retort area and to agitate the ilre bed. The retort, as shown in Fig. 2, is substantially U-shaped in transverse section and its rearward end is closed by means of an upwardly inclined wall I9 while its forward end terminates in a tubular portion adjacent the housing for screw I2.

An air chamber I5 surrounds the retort and in order that air for combustion may be directed into and across the top of the retort where combustion takes place, a tuyre I6 bridges the space between the side and end walls of the re- Y aciaims. (ci. 11o-44e) forward end of the feed screw I2 operates.

Y2 tort and air .chamber and is supported thereon. VAs mentioned the fuel to be fed to the retort I 0 is stored rin hopper I`I having an open bottom which is disposed over a housing Il in which the The feed screw lies in the bottom of the housing and is mounted in a bearing 18' secured in the rear walle20 thereof. `The1opposite wall 1 of housing I1 has an opening 2I through which screw I2 projects into the feed screw housing. As shown, the feed screw housing is secured to housing I7 and to end wall 22 of the air chamber I5 so that it will be held in the proper operating position and in alignment throughout its full length,

Since the feed screw is driven at a relatively low speed, one or two revolutions per minute for example, the screw is driven from motor 23 through a speed reducer or gear reduction mechanism 24 of any standard design suitable for the purpose. As shown in Fig. 1, the feed screw I2 terminates at the entrance to the retort and is confined almost wholly within the housing.

In order to secure uniform distribution of the incoming fuel to all parts of the retort, and also to secure agitation of the fire bed, the movable pusher bar I3 is given a reciprocating motion. The bar I3 with its members I4, while reciprocating, rakes the fuel to and fro while advancing it in the retort causing the same to be uniformly distributed throughout the length of the retort and over its fuel burning area, and prevents piling up of the fuel at different points longitudinally of the retort. Since members I4 extend upwardly from bar I3, the re bed is agitated sufficiently to prevent caking of the re bed. Bar I3 with its agitating or raking members I4, thus, in effect; functions as a sliding bottom.

The pusher bar I3 is reciprocated longitudinally of the retort by means of connecting rod 30 provided with a roller 3| which engages rotating cam 32. Cam 32 is fastened to power take-off shaft 33-and is rotated thereby and because of its contour produces a wobbling movement which causes roller 3l and with it rod 30, to reciprocate. Rod 30 is supported by bearings 34 and 35 and bar I3 is .supported at its rearward end by bearing 36 and at its forward end by bearing 31.

Heretofore the fuel worked into the space between the bar and the bottom of the retort, accumulatively packed there, and exerted an upward pressure on the bar. This pressure tended to lift the bar and to bend it upwardly and caused power consumed for driving the stokers. In some cases this strain has broken shear bolts in the driving mechanism and has broken bearing supports.

In the preferred form of the invention, pusher bar I3 is somewhat triangular in transverse section within the limits of the retort with the apex of the triangle disposedlowermostyas shownin" Fig. 2. This reducesrthel area under`which'fuel may pack. Also, preferably, at spaced intervals along said bar within the limits of the retort aref triangular members 40 extending on both ysides of the bar i3 which complete the bar to form a' the body portion of the bar. Asbar v13g-is recipro cated the extensions 40 act as plows, pushing the coal aside. By the 4combination of the' plow f 20 extensions 40 and the small area of bar I3 which faces the bottemdl: of retort -il ll" thetende'ncy for the coal to pack under thelbarlhasrbeen sofminimizedI as to practicallyeliminate theV diiiculties end thereof ;a pusher bar in the retort havingA a generally triangular transverse section within the limits of the retort with the apex disposed adjacent the bottom of the retort; and members extending on both sides of the bar at spaced intervals to form thereat generally rectangular transverse sections and large llets between the extending members and the bar.

2.:In' an un'derfeed steiger havin'garetort and means forMdeliveri-ng the" felto the retort to one end thereof; a pusher bar mounted adjacent the bottom of the retort for longitudinal reciprocationtherein having a generally rectangular transve`r"se"`secti'on with concave indentations at spaced iintervalsliextendngri into the lower portions of bothsides andthe bottom side of the bar.

JOHN S. SKELLY.

R'RNCES CITED Theron-owing references are of record in the file of this patent; g y ,Y y..

UNI'T'I; statesmen@ f Number Name Datel Y 644,664 Daley Mar.- 6, 1900 913,771 Ro'e` Manz; 1909 1,206,07111 Wood Nov. 28, 1916 1,766,056. Dady. June- 24, A1930 1,085,630 Rait Feb. 3; 1914 

